/Engine/Plugins/Online/OnlineSubsystem/Source/Public/OnlineNotificationHandler.h
The first parameter is a notification structure Return result code to indicate if notification has been handled
typedef TBaseDelegate_OneParam< [EOnlineNotificationResult](API\Plugins\OnlineSubsystem\EOnlineNotificationResult), const [FOnlineNotification](API\Plugins\OnlineSubsystem\FOnlineNotification) & > FHandleOnlineNotificationSignature